


Ante Astra

by Evandar



Series: Constellations [2]
Category: Harry Potter - J. K. Rowling
Genre: AU - Alphard Black Dies Earlier, Consensual Underage Sex, Don't copy to another site, Frottage, M/M, Pureblood Culture (Harry Potter), Referenced Child Neglect, Referenced Minor Character Death, Seer Regulus Black, Sibling Incest, The Noble and Most Ancient House of Black
Language: English
Status: Completed
Published: 2020-06-19
Updated: 2020-06-19
Packaged: 2021-03-03 21:53:06
Rating: Mature
Warnings: Underage
Chapters: 1
Words: 3,126
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24812620
Author URL: https://archiveofourown.org/users/Evandar/pseuds/Evandar
Summary: The morning after the night before. Sirius is nothing if not recklessly devoted.
Relationships: Alphard Black/Orion Black - implied, Regulus Black/Sirius Black
Series: Constellations [2]
Series URL: https://archiveofourown.org/series/1738408
Comments: 23
Kudos: 393





	Ante Astra

**Author's Note:**

> This is a direct sequel to the previous fic in this series, so if you haven't read that yet then this won't make much sense.

He wakes warm and slow, Regulus curled close to his body. His brother’s head is tucked into the curve of his neck, his hair tangled over Sirius’s face. He makes no move to brush it away. Regulus’ legs are twisted with his own, his breathing is slow and deep, and he’s tracing the lines of Sirius’ palm in his sleep. 

It tickles more than his hair does. 

Sirius keeps his eyes closed and his body still, tries to mimic Regulus’ deep breaths. They haven’t shared a bed in years - not since the year before Sirius started Hogwarts - but Regulus’ presence is oddly soothing. It shouldn’t be. Today, Sirius knows, their actions are going to catch up with them. He should be panicking - he feels like he should be _running_ \- but he can’t bring himself to pull away. 

The day their parents insisted on separate rooms was the first and last time he ever saw Regulus throw a tantrum. 

They’d both been punished. Regulus for his tears and Sirius for attempting to defend him. His mother’s hex had made him bite through his tongue to stop himself crying, and he can still remember the taste of his blood and the look on her face as she’d stood over them with her wand drawn. It was the same look she’d worn at Uncle Alphard’s funeral: a quiet satisfaction, the faint curl of a smile that made her look almost beautiful. 

Sirius wonders what curses she’ll have for them today. The news won’t stay quiet. As much as he wants to stay in the tangle of their limbs and sheets, he knows that they can’t. News of their engagement will be spreading through the family: as soon as Grandfather Arcturus puts quill to parchment and signs off on their betrothal contract, every copy of their family tree will change to reflect it. Sirius Orion Black engaged to Regulus Arcturus Black - the main branch of the family incestuously secured. 

He breathes out slowly, breath shaking towards the end. He curls his fingers around Regulus’, stopping the repetitive tracing of his heart line. Regulus sniffles softly in response, squirming closer and pressing the tip of his pointed nose against Sirius’ collar bone. 

There’s something else pressing against his thigh that Sirius is very much not thinking about. He may have agreed to marry Regulus - may, for that matter, have come up with the idea himself - and he may have kissed him last night, but...

But.

It’s one of those things that he’s going to have to _learn_ to think about. Things like the softness of Regulus’ lips and the prettiness of his blushes; the way his brother smiles; the way Regulus reaches for him – has always reached for him – and the way he curls so close. He’s going to have to learn to see Regulus as a lover as well as a brother. Regulus _loves_ him, and while Sirius had first thought of their engagement as a way to save him, that doesn’t mean Regulus doesn’t deserve to be happy.

They both deserve to be happy.

He lets his eyes open slowly. His eyelashes catch in Regulus’ hair, and through the blur of curling black strands, he can see light filtering through a gap in the bedcurtains. It’s time to get up. Time to go to breakfast and face the consequences of his impulses. He doesn’t want to. He wants to lie here forever, Regulus in his arms, warm and safe and quiet.

“You think so _loudly_ ,” Regulus murmurs. His words wash over Sirius’ chest, making his nipples peak and his skin tingle.

“That would be the panic,” Sirius tells him. He reaches up to finally brush Regulus’ hair off his face. It’s soft and silky, and he can’t resist carding his fingers through it. Regulus hums in response, pressing closer. His erection pushes against Sirius’ thigh, only the thin silk of his underwear between them. A lump lodges itself in Sirius’ throat even as heat flares in his belly.

He can’t stop himself from remembering the kiss they’d shared the previous night. The soft press of Regulus’ lips, the way his brother had gasped against him and then blushed so beautifully in the aftermath. They’d only kissed once, chastely, before retiring to bed – nothing that should have been as exciting as it suddenly seems.

He tightens his grip on Regulus’ hair, scraping his nails over his brother’s scalp. Regulus lifts his head. His hand slips from Sirius’ grasp and slides up his belly to rest over his heart.

Regulus’ eyes are dark, but he doesn’t move. He holds himself steady, and lets Sirius come to him; lets Sirius pull him down into a kiss; lets Sirius pull him closer by the hip. He moans softly as Sirius licks into his mouth, and he goes willingly when Sirius rolls them, positioning himself over him.

“Is this - ?” Sirius can’t quite bring himself to finish the question. It’s stupid, he knows: Regulus’ crush on him is practically legendary amongst family, and while his brother may be meek enough around their mother, he’s hardly a shrinking violet. If Regulus didn’t want this, Sirius would be a smear on the opposite wall. 

Not to mention, Regulus is ruthless when it comes to Sirius’ various displays of stupidity.

Still, he needs to know. Needs Regulus to tell him that his kisses are welcome, that the weight of Sirius on top of him is something he desires. He needs Regulus to _tell him_ that he’s wanted, even though the damp cling of silk to the head of Regulus’ prick is a fairly big clue that he is.

Regulus’ hand slides down from his heart, lower across his stomach. His fingers dip into the waistband of Sirius’ underwear and he tugs, teasing. “We probably shouldn’t,” he says. “Gods know what’s going to be in the contract.”

He sounds flustered, breathless, and through the swooping sensation in his belly and the fizzing in his blood, Sirius realises he likes it. _He_ made Regulus sound like that. _He_ ’s the one pressing his brother to the bed, gazing down into dark, dark eyes. _He_ ’s the one who made Regulus look and sound so debauched.

He…he _wants_ this. He wants Regulus. 

He wants Regulus, which is unfortunate, because Regulus has a point. Marriage contracts in the House of Black are hardly simply things, no matter how few families are involved in the process, and they are notoriously fickle.

He groans, sagging down against his brother’s body, trapping his hand between them. Regulus wiggles his fingers, but Sirius doesn’t move. Like this, he can feel every one of Regulus’ breaths, hear the beating of his heart. He can feel the long line of his erection pressed hot and snug against his own.

“Thank you,” Regulus murmurs.

“Hmm?”

“For this,” he says. “I didn’t thank you properly last night. And for this. I know you don’t –” He arches his back, pressing up against Sirius in a slow, sweet grind of hips that leaves Sirius feeling breathless. “You’re adjusting very quickly, brother.”

Sirius lets his actions speak for him. He kisses him again. He takes his time, exploring his brother’s mouth until Regulus is left panting, rocking his hips up to meet Sirius’ with every languid thrust. His brother’s hand, still trapped between them, curls in the waistband of his underwear, tugging desperately downwards. Sirius keeps his own hands above the waist: balancing his weight on one while the other remains twisted in Regulus’ hair. He breaks the kiss, uses his hold to drag Regulus’ head back. He kisses down the length of Regulus’ throat, nipping at the soft flesh and listening to his brother _beg_.

The heat in his belly is tightening. He thrusts harder. Regulus wraps one of his legs around his waist and digs his heel into Sirius’ arse, dragging him closer. His breath is coming in rough pants – he’s _mewling_ “oh, oh Sirius, yes, I, oh,” his voice cracking. He cries out when Sirius bites down, writhes and arches as Sirius sucks a hickey onto the base of his neck.

Sirius lifts his head to admire his handiwork. The mark is red and swollen, just like his lips; Regulus’ eyes are dark and glazed, and there’s a flush staining his cheeks and spreading down his chest.

He’s _gorgeous_.

Sirius leans back down to kiss him again. Regulus kisses back, eager and sloppy; panting please for more and harder against Sirius’ lips. Sirius obeys, rutting hard against his brother until Regulus stiffens. His cries turn higher, more desperate, and the leg around his waist tightens as Regulus arches up against him and comes. 

Sirius can feel it: wet heat soaking through their underwear, dampening their skin. He grinds his hips down against Regulus, listens as his brother whines softly at the overstimulation. It doesn’t take him long to finish. Regulus is beautiful and pliant and he’s watching Sirius like he’s the one who single-handedly threaded stars throughout the sky. It’s a heady thing. Irresistible. He comes hard, and his arms tremble as his hips still. Regulus groans at the sensation, licking his lips as if on reflex, and Sirius can’t help but wonder if he could talk Regulus into giving him a blowjob next time.

His cock twitches at the thought.

Regulus, the _bastard_ , has to feel it – he raises an eyebrow and grins before leaning up and kissing him again.

“Thank you,” he whispers. 

Sirius grins against his lips. “Any time,” he says.

…

The love-bite on Regulus’ neck is, mercifully, hidden by the starched collar of his undershirt. The redness of his kiss-swollen lips is not; neither is his mood, which is disturbingly chipper under all the pureblood etiquette. Not even being forced to share the breakfast table with Grandfather Arcturus and looking at his decaying hands over morning tea has dampened it. Nor did the knowing wink from Granny Melania when they entered together. Honestly, Sirius thinks he could be projecting a little – he knows fine well that he’s nowhere near as nervous as he had been when he first woke up, or as nervous as he probably should be – but he knows he isn’t. There’s a tiny smirk curling at the corner of Regulus’ mouth. A satisfied, smug little thing that nags at him to try and kiss it away.

One orgasm. One orgasm was apparently all it took to have him smitten.

Once the toast and the porridge are done with, their Grandfather looks up from his final cup of tea. The way he looks at them makes Sirius’ neck prickle as all his hair stands on end. There’s nothing quite like being looked at by someone who can see your soul. 

“Your contract will be signed this morning,” Grandfather Arcturus says. His voice, as ever, is little more than a whisper. “Do you wish your parents to be present?”

Sirius never wishes for their parents to be present. Or, rather, he never wishes for their _mother_ to be present. He’d much rather she be dropped in a heavily warded, lead-lined box to the ocean floor. Their father, on the other hand…

Their father wasn’t so bad, sometimes. When Uncle Alphard was still alive and their mother was absent, he almost had something of a personality. He’s a clever, quiet, watchful man who keeps the entire world except for Uncle Alphard at arm’s length. But Uncle Alphard is dead and their father is going to grieve himself into following, if Sirius’ instincts are correct, and their father has never been the most enthusiastic of parents. Maybe if they’d been Alphard’s children instead of Walburga’s… 

“No, thank you,” Regulus says. “Not until the contract is settled.”

Sirius feels a swell of relief that he’s not the only one to feel that way. “Mother will likely object to the clause forbidding us to enter bonds of allegiance,” he says. 

Grandfather hums softly, while Granny scoffs. “Walburga’s a shrew,” she says. “ _I’d_ rather she was kept as far away from proceedings as possible, and it’s not my contract.”

Bless the gods for Granny Melania.

A Macmillan at birth, she stands out in the family for being the only one with an alignment for Light magic. It was her blood that stopped Grandfather’s gift for necromancy being passed on, which Sirius can only really be thankful for. But Light witch or not, she’s _terrifying_. Warm and round and cheerful right up until she destroys your entire life. She’d done something, once, a long time ago, that involved a chirpy smile and a homemade scone that – for some reason – sends Aunt Cassie into a fit of the vapours every time anyone mentions bilberry jam.

And considering family legend says Aunt Cassie had been blackmailing Grindelwald at one point…

“I find her insistence that Regulus bows to this…Dark Lord of hers…worrying,” Grandfather Arcturus murmurs.

Granny Melania sniffs. “A Black bowing to someone hiding behind a false name,” she says. “The _shame_.”

“I’ll be dead before I’m twenty if I do,” Regulus says.

Sirius can’t help it. He turns to look at Regulus so quickly that his neck hurts. He’d known…he’d known Regulus hadn’t been happy; that he’d been reluctant to follow their mother’s instructions to go to the rally, even though he’d been going to obey. He hadn’t realised that Regulus had foretold his own death.

Not for the first time, he wonders what awful secrets Regulus keeps in that little black book of his.

He doesn’t ask, however. Regulus is wilting slightly under the combined aghast stares of Sirius and their grandparents. The pretty, smug little smile from earlier has vanished, and he’s studying his tea as if it’s going to tell him the secrets of the universe.

It might, for all Sirius knows.

He reaches out slowly and rests his hand on Regulus’ thigh. He squeezes gently, and the tiniest hint of that smile returns as Regulus turns to look at him.

He likes it. He likes Regulus’ smile. Gods help him, he wants so very much to keep it.

He takes a breath. “Perhaps, Grandfather, we might be permitted to stay with you for the rest of the summer,” he says.

Regulus’ smile widens.

…

Sirius isn’t Seeker material. He’s a Beater, and a good one. His brother, on the other hand, is the best damn Seeker in Hogwarts.

It’s making their match distinctly unfair.

Making it harder is the fact that none of their illustrious ancestors thought to build a Quidditch pitch at Black Castle. It’s not a particularly _surprising_ feature: personal Quidditch pitches are rather in the realms of the _nouveau_ \- families like the Potters and the Malfoys and the Yaxleys, who are all fabulously wealthy while not being as deeply trenched in archaic traditions. It’s not even something that’s bothered Sirius before, but then, he’s never been tempted to look for a Snitch released outside of pitch wards before. This one, Regulus’ practice Snitch, has been granted the use of the whole of the castle grounds. It’s occurred to him more than once, as he’s looped his way around turrets and battlements, that they may never actually see it again.

He flies higher. Higher. Right up to the boundaries of the wards.

From here, he can see everything. The castle sprawled out over the earth, dark and forbidding and entirely too complicated. The complex has been expanded over thousands of years, built over and out without any noticeable pattern. He can see the earthworks for the hillfort it was built on, the avenue that leads to the stone circle – the Sisters – and then stretches out, beyond it, to the cairn. He can see, even from this distance, the cold tendrils of sentient death magic spilling from the entrance.

Further away, where the wards end, he can see the village, Aldgrim, nestled between the magic of the Blacks and the wild woods, with the snow-capped Black Mountains rising up behind them. It’s always struck him as a very precarious place to live, although the few times he’s been to the village, none of the Muggles have seemed to care too much.

Though, they do give away a lot of things for free.

Regulus soars up to meet him. He’s not clasping a Snitch in his hand and there’s a slightly rueful expression on his face that says he knows _exactly_ what a terrible idea this was and that they’ll probably still be hunting for the Snitch in their thirties.

At least now, Regulus might see his thirties.

The thought makes a lump rise in his throat, and when Regulus reaches him, he reaches out, tangling his fingers in his brother’s robes and guiding him closer. Their knees brush. Regulus wraps one of his hand around Sirius’ broom handle; uses the other to push Sirius’ hair out of his face as Sirius pulls him in, closer, ever closer until they’re kissing – soft and sweet and freezing their arses off in the high altitude and cold wind.

It’s worth it. The cold makes the warmth of Regulus’ mouth seem all the sweeter, and Sirius groans into it, slipping his arm around Regulus’ waist. He can feel his hair catching on Regulus’ brand-new ring as his brother grips him tight.

With their contract signed and sealed, they’d been allowed to select rings from the collection kept in the secret chamber beneath Grandfather’s study. Regulus had chosen the Sirius Ring for himself – binary diamonds set flush in platinum – and he’d grinned like an idiot when Sirius had slipped it onto his finger. Sirius’ own ring, set with a red diamond and engraved on the inside with the constellation of Leo, feels odd on his hand. Heavy at times, but valuable. Irreplaceable. He’s caught himself seeking reassurance by rubbing his thumb against the warm metal more than once already, and he’s only had it on for three hours.

For all that this game is to get them out of the castle, for all that they’re avoiding their mother’s shrieked objections to the match through the Floo – for all that the betrothal was just to make sure Regulus wouldn’t have to kiss the robe hems of a blood-supremacist _dick_ … it feels right between them. As if something Sirius hadn’t noticed was missing has been returned.

“You’re happy,” Regulus says when their kiss breaks, his voice barely audible over the wind.

Sirius just grins at him.

He has five whole weeks of happiness in front of him. Five, glorious weeks with Regulus in his arms and his bed, and their mother on the other side of the country. Five weeks before school starts and his friends find out that Sirius is very much still a Black after all.

After that?

He’ll just have to cling to the happiness Regulus brings him.


End file.
